The present invention relates to an optical switching system and, more particularly, to an optical switching system for connecting a plurality of subscribers or terminal equipment with each other by optical signals. In more detail, the invention relates to an optical switching system in which the subscribers or terminal equipment are connected with the optical switching system by use of fiber optic cables and the signal exchange in the switching unit is performed without converting the signal into the electric signal.
In association with the spread of the signal transmission using optical fibers, the optical communication network system including the signal exchange has been examined. In particular, it is presumed that the application of the optical technology to the local switch and toll switch as the central node of the services to the subscribers will give a large impact toward the future era of digital integration of the network system. As a final format, the realization of the optical switching system for directly switching the optical signals from the fiber optic cable is demanded. The study of such an optical switching system has just been started but several ideas have been reported.
However, in the conventional optical switching systems proposed, electric signals are used in the multiplexer and demultiplexer for coupling the lines of a plurality of subscribers with the optical switching system. Namely, the communication between a plurality of subscriber lines and the multiplexer or demultiplexer is performed by the electric signals.
Since the signal paths in the switching system are constituted as the opto-electric hybrid system, this constitution obstructs the realization of the ultra high speed, broad band, and ultra multi-channel transmission. In addition, the opto-electric hybrid system causes such a problem that the maintenance and handling are difficult.
On the other hand, no consideration is paid to the signal exchange of high speed and broad band information and the signal paths in the switching system are constituted as the opto-electric hybrid system. Thus, the realization of the ultra high speed, broad band, and ultra multi-channel transmission is obstructed. There is such a problem that the maintenace and handling are difficult.